80 



Studies on Synapsis. 



(17) Gatenby, 1920 : " On the Relationship between the Formation of Yolk and the 



Mitochondria, etc.," ' Q. J. Roy. Micr. Soc.'. 



(18) Hirechler, 1915 : "Ueber ein Verfahren zur gleichzeitigen Darstellung des 



Golgischen Apparates, usw.," ' Zeit. f. Wiss. Mikr. und Tech.,' vol. 32. 



(19) Nusbaum Hilarowicz, 1917 : " Ueber das Verhalten des Chondrioms waihrend der 



Eibildung bei Dytiscus," ' Zeit. f. Wiss. Zool.,' 



(20) Beckwith, 1914: "The Genesis of the Plasma Structures in the egg of Hydrac- 



tinia," ' Journ. Morph.,' vol. 25. 



EXPLANATION OF PLATES. 



Fig. 1. — Spermatogonial metaphase : 23 chromosomes and two granules ? nucleolar in 

 origin. 2. — Do., anaphase. 3-5.- — Telophase : p, plasmosome. 6. — Spirophase. 

 7-10. — Prophase. 11. — Spermatocyte: Leptotene stage, X, X-chromosome. 

 12. — Contraction phase. 13. — Do., pachytene. 14-15. — Diploteue stage. 16. — Dis- 

 solution of bouquet. 17-18. — Genesis of tetrads. 19-22. — Heterotype mitosis. 

 23-25. — Second reduction division with 11 and 12 chromosomes. 26. — Oogonial 

 prophase. 27. — Metaphase with 24 chromosomes. 28. — Oocyte : leptotene stage. 

 29. — Zygonema. 30. — Maximal contraction. 31. — T.S., late pachytene stage. 

 32. — Diplotene stage (post-synaptic). 33-35. — Genesis of pro-tetrads and inception 

 of the diffuse stage. 36. — Oocyte in growth period with double nucleolus 

 {p), nucleus-like intranucleolar oxyphil body (o), chromatic network (cr), deutosomes 

 in nucleus and cytoplasm («?). Flemming. 37. — Do., showing formation of the 

 oxyphil body. Flemming. 38. — Oocyte at inception of growth period with yolk 

 nucleus or mitosome. Mann-Kopsch. 39. — T.S. older egg, mitochondrial area (m). 

 F. W.A. 



